InterPro domain: IPR017852

This entry represents the C-terminal region of GPI ethanolamine phosphate transferase 1 enzymes, including the yeast enzyme MCD4 and the mammalian homolgoue PIG-N (also known as phosphatidylinositolglycan class N) [ 1 , 2 ]. These enzymes are multi-pass endoplasmic reticulum membrane proteins involved in glycosylphosphatidylinositol (GPI)-anchor biosynthesis. These enzymes transfer ethanolamine phosphate to the first alpha-1,4-linked mannose of the GPI precursor of the GPI-anchor. Ethanolamine phosphate on the alpha-1,4-linked mannose is essential for further mannosylation by GPI10 and is necessary for an efficient recognition of GPI lipids and GPI proteins by the GPI transamidase, for the efficient transport of GPI anchored proteins from endoplasmic reticulum to Golgi and for the physiological incorporation of ceramides into GPI anchors by lipid remodeling. MCD4 is also involved in non-mitochondrial ATP movements across the membrane and participates in Golgi and endoplasmic reticulum function, and is required for the incorporation of BGL2 into the cell wall.

1. Pig-n, a mammalian homologue of yeast Mcd4p, is involved in transferring phosphoethanolamine to the first mannose of the glycosylphosphatidylinositol. J. Biol. Chem. 274, 35099-106
2. MCD4 encodes a conserved endoplasmic reticulum membrane protein essential for glycosylphosphatidylinositol anchor synthesis in yeast. Mol. Biol. Cell 10, 627-48